﻿using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.OleDb;
using System.Collections;
using System.IO;



namespace DAL
{
    public class SqlHelper
    {
        private static readonly string constr = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + Directory.GetCurrentDirectory() + "\\案例库.accdb;Jet OLEDB:Database Password=123";
            //ConfigurationManager.ConnectionStrings["strCon"].ConnectionString;

        OleDbConnection cn = new OleDbConnection(constr);
        OleDbCommand cmd = new OleDbCommand();
        OleDbTransaction transaction = null; 
        public static System.Data.OleDb.OleDbConnection CreateConnection()
        {
            OleDbConnection connection = new OleDbConnection(constr);
            return connection;
        }
      

        #region 公用方法    
  
        public static int GetMaxID(string FieldName, string TableName)    
        {    
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = SqlHelper.GetSingle(strsql);    
            if (obj == null)    
            {    
                return 1;    
            }    
            else  
            {    
                return int.Parse(obj.ToString());    
            }    
        }    
        public static bool Exists(string strSql)    
        {
            object obj = SqlHelper.GetSingle(strSql);    
            int cmdresult;    
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))    
            {    
                cmdresult = 0;    
            }    
            else  
            {    
                cmdresult = int.Parse(obj.ToString());    
            }    
            if (cmdresult == 0)    
            {    
                return false;    
            }    
            else  
            {    
                return true;    
            }    
        }    
        public static bool Exists(string strSql, params OleDbParameter[] cmdParms)    
        {
            object obj = SqlHelper.GetSingle(strSql, cmdParms);    
            int cmdresult;    
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))    
            {    
                cmdresult = 0;    
            }    
            else  
            {    
                cmdresult = int.Parse(obj.ToString());    
            }    
            if (cmdresult == 0)    
            {    
                return false;    
            }    
            else  
            {    
                return true;    
            }    
        }  
        #endregion  
  
        #region  执行简单SQL语句    
  
        /// <summary>    
        /// 执行SQL语句，返回影响的记录数（加入事务）    
        /// </summary>    
        /// <param name="SQLString">SQL语句</param>    
        /// <returns>影响的记录数</returns>    
        public static int ExecuteSql(string SQLString)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                //using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))    
                //{
                connection.Open();    
                OleDbCommand cmd = new OleDbCommand();
                cmd.CommandText = SQLString;
                cmd.Transaction = connection.BeginTransaction();
                cmd.Connection = connection;
                    try  
                    {
                        //cmd.Transaction = connection.BeginTransaction();
                        //connection.Open();    
                        int rows = cmd.ExecuteNonQuery();
                        if (rows < 0)
                            throw new Exception();
                        cmd.Transaction.Commit();
                        return rows;    
                    }    
                    catch (System.Data.OleDb.OleDbException E)
                    {
                        cmd.Transaction.Rollback(); 
                        connection.Close();    
                        throw E;
                    }    
                //}    
            }    
        }    
  
        /// <summary>    
        /// 执行SQL语句，设置命令的执行等待时间    
        /// </summary>    
        /// <param name="SQLString"></param>    
        /// <param name="Times"></param>    
        /// <returns></returns>    
        public static int ExecuteSqlByTime(string SQLString, int Times)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))    
                {    
                    try  
                    {    
                        connection.Open();    
                        cmd.CommandTimeout = Times;    
                        int rows = cmd.ExecuteNonQuery();    
                        return rows;    
                    }    
                    catch (System.Data.OleDb.OleDbException E)    
                    {    
                        connection.Close();    
                        throw new Exception(E.Message);    
                    }    
                }    
            }    
        }    
  
        /// <summary>    
        /// 执行多条SQL语句，实现数据库事务。    
        /// </summary>    
        /// <param name="SQLStringList">多条SQL语句</param>        
        public static void ExecuteSqlTran(ArrayList SQLStringList)    
        {
            using (OleDbConnection conn = new OleDbConnection(constr))    
            {    
                conn.Open();    
                OleDbCommand cmd = new OleDbCommand();    
                cmd.Connection = conn;    
                OleDbTransaction tx = conn.BeginTransaction();    
                cmd.Transaction = tx;    
                try  
                {    
                    for (int n = 0; n < SQLStringList.Count; n++)    
                    {    
                        string strsql = SQLStringList[n].ToString();    
                        if (strsql.Trim().Length > 1)    
                        {    
                            cmd.CommandText = strsql;    
                            cmd.ExecuteNonQuery();    
                        }    
                    }    
                    tx.Commit();    
                }    
                catch (System.Data.OleDb.OleDbException E)    
                {    
                    tx.Rollback();    
                    throw new Exception(E.Message);    
                }    
            }    
        }    
  
        /// <summary>    
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)    
        /// </summary>    
        /// <param name="strSQL">SQL语句</param>    
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>    
        /// <returns>影响的记录数</returns>    
        public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                OleDbCommand cmd = new OleDbCommand(strSQL, connection);    
                System.Data.OleDb.OleDbParameter myParameter = new System.Data.OleDb.OleDbParameter("@fs", SqlDbType.Image);    
                myParameter.Value = fs;    
                cmd.Parameters.Add(myParameter);    
                try  
                {    
                    connection.Open();    
                    int rows = cmd.ExecuteNonQuery();    
                    return rows;    
                }    
                catch (System.Data.OleDb.OleDbException E)    
                {    
                    throw new Exception(E.Message);    
                }    
                finally  
                {    
                    cmd.Dispose();    
                    connection.Close();    
                }    
            }    
        }    
  
        /// <summary>    
        /// 执行一条计算查询结果语句，返回查询结果（object）。    
        /// </summary>    
        /// <param name="SQLString">计算查询结果语句</param>    
        /// <returns>查询结果（object）</returns>    
        public static object GetSingle(string SQLString)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))    
                {    
                    try  
                    {    
                        connection.Open();    
                        object obj = cmd.ExecuteScalar();    
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))    
                        {    
                            return null;    
                        }    
                        else  
                        {    
                            return obj;    
                        }    
                    }    
                    catch (System.Data.OleDb.OleDbException e)    
                    {    
                        connection.Close();    
                        throw new Exception(e.Message);    
                    }    
                }    
            }    
        }      
  
        /// <summary>    
        /// 执行查询语句，返回SqlDataReader(使用该方法切记要手工关闭SqlDataReader和连接)    
        /// </summary>    
        /// <param name="strSQL">查询语句</param>    
        /// <returns>SqlDataReader</returns>    
        public static OleDbDataReader ExecuteReader(string strSQL)    
        {
            OleDbConnection connection = new OleDbConnection(constr);    
            OleDbCommand cmd = new OleDbCommand(strSQL, connection);    
            try  
            {    
                connection.Open();    
                OleDbDataReader myReader = cmd.ExecuteReader();    
                return myReader;    
            }    
            catch (System.Data.OleDb.OleDbException e)    
            {    
                throw new Exception(e.Message);    
            }    
            //finally //不能在此关闭，否则，返回的对象将无法使用    
            //{    
            //  cmd.Dispose();    
            //  connection.Close();    
            //}      
        }    
        /// <summary>    
        /// 执行查询语句，返回DataSet    
        /// </summary>    
        /// <param name="SQLString">查询语句</param>    
        /// <returns>DataSet</returns>    
        public static DataSet Query(string SQLString)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                DataSet ds = new DataSet();    
                try  
                {    
                    connection.Open();    
                    OleDbDataAdapter command = new OleDbDataAdapter(SQLString, connection);    
                    command.Fill(ds, "ds");    
                }    
                catch (System.Data.OleDb.OleDbException ex)    
                {    
                    throw new Exception(ex.Message);    
                }    
                return ds;    
            }    
        }    
        /// <summary>    
        /// 执行查询语句，返回DataSet,设置命令的执行等待时间    
        /// </summary>    
        /// <param name="SQLString"></param>    
        /// <param name="Times"></param>    
        /// <returns></returns>    
        public static DataSet Query(string SQLString, int Times)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                DataSet ds = new DataSet();    
                try  
                {    
                    connection.Open();    
                    OleDbDataAdapter command = new OleDbDataAdapter(SQLString, connection);    
                    command.SelectCommand.CommandTimeout = Times;    
                    command.Fill(ds, "ds");    
                }    
                catch (System.Data.OleDb.OleDbException ex)    
                {    
                    throw new Exception(ex.Message);    
                }    
                return ds;    
            }    
        }  
  
        #endregion  
  
        #region 执行带参数的SQL语句    
  
        /// <summary>    
        /// 执行SQL语句，返回影响的记录数    
        /// </summary>    
        /// <param name="SQLString">SQL语句</param>    
        /// <returns>影响的记录数</returns>    
        public static int ExecuteSql(string SQLString, params OleDbParameter[] cmdParms)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                using (OleDbCommand cmd = new OleDbCommand())    
                {    
                    try  
                    {    
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);    
                        int rows = cmd.ExecuteNonQuery();    
                        cmd.Parameters.Clear();    
                        return rows;    
                    }    
                    catch (System.Data.OleDb.OleDbException E)    
                    {    
                        throw new Exception(E.Message);    
                    }    
                }    
            }    
        }      
  
        /// <summary>    
        /// 执行多条SQL语句，实现数据库事务。    
        /// </summary>    
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的OleDbParameter[]）</param>    
        public static void ExecuteSqlTran(Hashtable SQLStringList)    
        {
            using (OleDbConnection conn = new OleDbConnection(constr))    
            {    
                conn.Open();    
                using (OleDbTransaction trans = conn.BeginTransaction())    
                {    
                    OleDbCommand cmd = new OleDbCommand();    
                    try  
                    {    
                        //循环    
                        foreach (DictionaryEntry myDE in SQLStringList)    
                        {    
                            string cmdText = myDE.Key.ToString();    
                            OleDbParameter[] cmdParms = (OleDbParameter[])myDE.Value;    
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);    
                            int val = cmd.ExecuteNonQuery();    
                            cmd.Parameters.Clear();    
  
                            trans.Commit();    
                        }    
                    }    
                    catch  
                    {    
                        trans.Rollback();    
                        throw;    
                    }    
                }    
            }    
        }      
  
        /// <summary>    
        /// 执行一条计算查询结果语句，返回查询结果（object）。    
        /// </summary>    
        /// <param name="SQLString">计算查询结果语句</param>    
        /// <returns>查询结果（object）</returns>    
        public static object GetSingle(string SQLString, params OleDbParameter[] cmdParms)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                using (OleDbCommand cmd = new OleDbCommand())    
                {    
                    try  
                    {    
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);    
                        object obj = cmd.ExecuteScalar();    
                        cmd.Parameters.Clear();    
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))    
                        {    
                            return null;    
                        }    
                        else  
                        {    
                            return obj;    
                        }    
                    }    
                    catch (System.Data.OleDb.OleDbException e)    
                    {    
                        throw new Exception(e.Message);    
                    }    
                }    
            }    
        }    /* 何问起 hovertree.com */
  
        /// <summary>    
        /// 执行查询语句，返回SqlDataReader (使用该方法切记要手工关闭SqlDataReader和连接)    
        /// </summary>    
        /// <param name="strSQL">查询语句</param>    
        /// <returns>SqlDataReader</returns>    
        public static OleDbDataReader ExecuteReader(string SQLString, params OleDbParameter[] cmdParms)    
        {
            OleDbConnection connection = new OleDbConnection(constr);    
            OleDbCommand cmd = new OleDbCommand();    
            try  
            {    
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);    
                OleDbDataReader myReader = cmd.ExecuteReader();    
                cmd.Parameters.Clear();    
                return myReader;    
            }    
            catch (System.Data.OleDb.OleDbException e)    
            {    
                throw new Exception(e.Message);    
            }    
            //finally //不能在此关闭，否则，返回的对象将无法使用    
            //{    
            //  cmd.Dispose();    
            //  connection.Close();    
            //}      
        }    
  
        /// <summary>    
        /// 执行查询语句，返回DataSet    
        /// </summary>    
        /// <param name="SQLString">查询语句</param>    
        /// <returns>DataSet</returns>    
        public static DataSet Query(string SQLString, params OleDbParameter[] cmdParms)    
        {
            using (OleDbConnection connection = new OleDbConnection(constr))    
            {    
                OleDbCommand cmd = new OleDbCommand();    
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);    
                using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))    
                {    
                    DataSet ds = new DataSet();    
                    try  
                    {    
                        da.Fill(ds, "ds");    
                        cmd.Parameters.Clear();    
                    }    
                    catch (System.Data.OleDb.OleDbException ex)    
                    {    
                        throw new Exception(ex.Message);    
                    }    
                    return ds;    
                }    
            }    
        }      
  
        private static void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, OleDbTransaction trans, string cmdText, OleDbParameter[] cmdParms)    
        {    
            if (conn.State != ConnectionState.Open)    
                conn.Open();    
            cmd.Connection = conn;    
            cmd.CommandText = cmdText;    
            if (trans != null)    
                cmd.Transaction = trans;    
            cmd.CommandType = CommandType.Text;//cmdType;    
            if (cmdParms != null)    
            {      
                foreach (OleDbParameter parameter in cmdParms)    
                {    
                    if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&    
                        (parameter.Value == null))    
                    {    
                        parameter.Value = DBNull.Value;    
                    }    
                    cmd.Parameters.Add(parameter);    
                }    
            }    
        }  
  
        #endregion  
  
        #region 获取根据指定字段排序并分页查询。    
  
  
        /* 何问起 hovertree.com */  
        /// <summary>    
        /// 分页查询数据记录总数获取    
        /// </summary>    
        /// <param name="_tbName">----要显示的表或多个表的连接</param>    
        /// <param name="_ID">----主表的主键</param>    
        /// <param name="_strCondition">----查询条件,不需where</param>            
        /// <param name="_Dist">----是否添加查询字段的 DISTINCT 默认0不添加/1添加</param>    
        /// <returns></returns>    
        public static string getPageListCounts(string _ID, string _tbName, string _strCondition, int _Dist)    
        {    
            //---存放取得查询结果总数的查询语句                        
            //---对含有DISTINCT的查询进行SQL构造    
            //---对含有DISTINCT的总数查询进行SQL构造    
            string strTmp = "", SqlSelect = "", SqlCounts = "";    
  
            if (_Dist == 0)    
            {    
                SqlSelect = "Select ";    
                SqlCounts = "COUNT(*)";    
            }    
            else  
            {    
                SqlSelect = "Select DISTINCT ";    
                SqlCounts = "COUNT(DISTINCT " + _ID + ")";    
            }    
            if (_strCondition == string.Empty)    
            {    
                strTmp = SqlSelect + " "+ SqlCounts + " FROM " + _tbName;    
            }    
            else  
            {    
                strTmp = SqlSelect + " "+ SqlCounts + " FROM " + " Where (1=1) " + _strCondition;    
            }    
            return strTmp;    
        }      
  
        /// <summary>    
        /// 智能返回SQL语句    
        /// </summary>    
        /// <param name="primaryKey">主键（不能为空）</param>    
        /// <param name="queryFields">提取字段（不能为空）</param>    
        /// <param name="tableName">表（理论上允许多表）</param>    
        /// <param name="condition">条件（可以空）</param>    
        /// <param name="OrderBy">排序，格式：字段名+""+ASC（可以空）</param>    
        /// <param name="pageSize">分页数（不能为空）</param>    
        /// <param name="pageIndex">当前页，起始为：1（不能为空）</param>    
        /// <returns></returns>      
        public static string getPageListSql(string primaryKey, string queryFields, string tableName, string condition, string orderBy, int pageSize, int pageIndex)    
        {    
            string strTmp = ""; //---strTmp用于返回的SQL语句    
            string SqlSelect = "", SqlPrimaryKeySelect = "", strOrderBy = "", strWhere = " where 1=1 ", strTop = "";    
            //0：分页数量    
            //1:提取字段    
            //2:表    
            //3:条件    
            //4:主键不存在的记录    
            //5:排序    
            SqlSelect = " select top {0} {1} from {2} {3} {4} {5}";    
            //0:主键    
            //1:TOP数量,为分页数*(排序号-1)    
            //2:表    
            //3:条件    
            //4:排序    
            SqlPrimaryKeySelect = " and {0} not in (select {1} {0} from {2} {3} {4}) ";      
            if (orderBy != "")    
                strOrderBy = " order by " + orderBy;    
            if (condition != "")    
                strWhere += " and " + condition;    
            int pageindexsize = (pageIndex - 1) * pageSize;    
            if (pageindexsize > 0)    
            {    
                strTop = " top " + pageindexsize.ToString();    
  
                SqlPrimaryKeySelect = String.Format(SqlPrimaryKeySelect, primaryKey, strTop, tableName, strWhere, strOrderBy);    
  
                strTmp = String.Format(SqlSelect, pageSize.ToString(), queryFields, tableName, strWhere, SqlPrimaryKeySelect, strOrderBy);    
  
            }    
            else  
            {    
                strTmp = String.Format(SqlSelect, pageSize.ToString(), queryFields, tableName, strWhere, "", strOrderBy);    
  
            }    
            return strTmp;    
        }      
  
        /// <summary>    
        /// 获取根据指定字段排序并分页查询。DataSet    
        /// </summary>    
        /// <param name="pageSize">每页要显示的记录的数目</param>    
        /// <param name="pageIndex">要显示的页的索引</param>    
        /// <param name="tableName">要查询的数据表</param>    
        /// <param name="queryFields">要查询的字段,如果是全部字段请填写：*</param>    
        /// <param name="primaryKey">主键字段，类似排序用到</param>    
        /// <param name="orderBy">是否为升序排列：0为升序，1为降序</param>    
        /// <param name="condition">查询的筛选条件</param>    
        /// <returns>返回排序并分页查询的DataSet</returns>    
        public static DataSet GetPagingList(string primaryKey, string queryFields, string tableName, string condition, string orderBy, int pageSize, int pageIndex)    
        {    
            string sql = getPageListSql(primaryKey, queryFields, tableName, condition, orderBy, pageSize, pageIndex);    
  
            return Query(sql);    
        }    
        public static string GetPagingListSQL(string primaryKey, string queryFields, string tableName, string condition, string orderBy, int pageSize, int pageIndex)    
        {    
            string sql = getPageListSql(primaryKey, queryFields, tableName, condition, orderBy, pageSize, pageIndex);    
  
            return sql;    
        }    
        public static int GetRecordCount(string _ID, string _tbName, string _strCondition, int _Dist)    
        {    
            string sql = getPageListCounts( _ID,  _tbName,  _strCondition,  _Dist);

            object obj = SqlHelper.GetSingle(sql);    
            if (obj == null)    
            {    
                return 1;    
            }    
            else  
            {    
                return int.Parse(obj.ToString());    
            }    
        }  
        #endregion    
    }
}
